1. Field of the Invention
The present invention relates to a snow removing machine, and more particularly to a self-propelled snow removing machine having a single engine for driving crawlers, an auger driven by the engine for clearing away snow, and a blower for discharging the snow.
2. Description of the Relevant Art
U.S. Pat. No. 4,514,917 discloses a self-propelled working vehicle such as a self-propelled snow removing tractor having a single engine for driving crawlers, an auger driven by the engine for clearing away snow, and a snow blower for discharging the snow. In the disclosed snow-removing tractor, the engine is operatively coupled to the crawlers through a first belt having a tensioner and a main transmission, and also to a drive shaft of the auger and the blower through a second belt having a tensioner.
The snow-removing tractor also has a subtransmission interposed between the engine and the main transmission, for selectively permitting the snow-removing machine to travel at a low speed while removing snow, and to run at a high speed while moving to and from a place where snow is to be removed. The second belt is trained around a pulley coupled to a rear end of the auger/blower drive shaft which extends longitudinally in a body frame housing the main transmission and others. The pulley is fixed to the end of the drive shaft within the body frame. The drive shaft is disposed in a blower housing, and the snow blower having radial fins is secured to the drive shaft in the blower housing. To the front end of the drive shaft, there is operatively coupled a transverse auger shaft through an auger transmission comprising a worm and a pinion meshing therewith. The opposite ends of the auger shaft are supported on an auger cover. The auger which comprises a plurality of fins is mounted on the auger shaft.
Since the auger/blower drive shaft and the engine are interconnected by the second belt having the tensioner, the engine has to be positioned upwardly near the driver to keep a distance over which the second belt lies. As a result, the center of gravity of the vehicle is positioned relatively high, and the field of view of the driver is obstructed by an upper portion of the engine.
The engine power is transmitted from the engine to the crawlers and the auger/blower drive shaft through the first and second belts with their tension adjusted by the respective tensioners. The belt tension adjustment and belt replacement must be effected relatively frequently, and hence the snow-removing tractor needs relatively frequent maintenance. Inasmuch as the engine crankshaft and the auger/blower drive shaft have to be spaced a relatively large distance from each other, the snow removing tractor is large in size. One proposal to eliminate the frequent maintenance of the second belt would be to couple the auger/blower drive shaft to the engine through a friction-type multiplate clutch. In view of the fact that the snow-removing tractor is used in cold climates, dry-type multiplate clutches would be more preferable than wet-type multiplate clutches as the latter generate drag torque after clutch disengagement. However, it would be impossible to place such a dry-type clutch and a transmission mechanism within a transmission case. Therefore, it would be necessary to provide a clutch housing separately from the transmission case, resulting in a larger tractor size and an increased cost of manufacture. Also, such a snow-removing tractor would have to be arranged to allow engine power to be transmitted to the auger and the snow blower only when a control lever would be operated. This would make it undesirable to use a general clutch in which power transmission elements such as friction plates are normally held in frictional contact. Instead, a special clutch that would meet the above requirement as to the timing of engine power transmission would be required, with the result that the cost of the entire snow-removing tractor would be high.
When the auger and the snow blower are to be assembled into the body frame, the housing for accommodating the auger and the snow-removing tractor is first brought against the body frame axially of the auger/blower drive shaft. Then, bolt holes defined in a marginal flange of the housing which faces the body frame and bolt holes defined in a marginal flange of the body frame which faces the housing are held in registry with each other. The housing is fastened to the body frame by bolts inserted through the registered bolt holes and nuts threaded over the bolts. This assembling process is relatively tedious and time-consuming. The pulley on the auger/blower drive shaft is usually fixed by a bolt to the rear end thereof which extends into the body frame. For replacing the auger and/or the blower, it is necessary to detach a side cover of the body frame and then remove the pulley from the rear end of the auger/blower drive shaft by loosening the bolt and nut. Removal of the pulley requires other associated components such as the second belt to be also detached. Therefore, replacement of the auger and/or the blower is labor intensive and so is the maintenance thereof.
The present invention has been made in an effort to solve the aforesaid problems of the conventional self propelled snow-removing tractor.